Vehicle control system with trainable transceiver

ABSTRACT

A trainable transceiver provides an integrated trainable transmitter and control system receiver for a vehicle electrical system. The transceiver includes an input circuit and an output circuit coupled to a controller. The transceiver also includes an interface connected between the controller and the vehicle&#39;s electrical system. The input circuit which receives RF signals includes an amplitude control for adjusting the reception range of the transceiver. The transceiver also disconnects the output circuit from the antenna in a remote control training mode or a transmitter signal detection mode. The transceiver is manually controlled to enter the remote control training mode and a transmission mode for controlling a remote device. The transceiver automatically enters the transmitter signal detection mode on a periodic basis.

RELATED APPLICATION

This application is a continuation-in-part of co-pending U.S. patentapplication Ser. No. 07/567,390 entitled ELECTRICAL CONTROL SYSTEM FORVEHICLE OPTIONS, filed on Aug. 14, 1990. This application is alsorelated to U.S. Pat. No. 5,442,340 entitled TRAINABLE RF TRANSMITTERINCLUDING ATTENUATION CONTROL issued Aug. 15, 1995, in the name of KurtDykema, now U.S. Pat. No. 5,442,340, which is a continuation-in-part ofapplication Ser. No. 07/874,361 entitled VEHICLE ACCESSORY TRAINABLETRANSMITTER, filed on Apr. 24, 1992, now U.S. Pat. No. 5,479,155, whichis a continuation-in-part of allowed application Ser. No. 07/567,390entitled ELECTRICAL CONTROL SYSTEM FOR VEHICLE OPTIONS, filed on Aug.14, 1990, the disclosures of which are incorporated herein by referencethereto.

RELATED APPLICATION

This application is a continuation-in-part of co-pending U.S. patentapplication Ser. No. 07/567,390 entitled ELECTRICAL CONTROL SYSTEM FORVEHICLE OPTIONS, filed on Aug. 14, 1990. This application is alsorelated to U.S. Pat. No. 5,442,340 entitled TRAINABLE RF TRANSMITTERINCLUDING ATTENUATION CONTROL issued Aug. 15, 1995, in the name of KurtDykema, now U.S. Pat. No. 5,442,340, which is a continuation-in-part ofapplication Ser. No. 07/874,361 entitled VEHICLE ACCESSORY TRAINABLETRANSMITTER, filed on Apr. 24, 1992, now U.S. Pat. No. 5,479,155, whichis a continuation-in-part of allowed application Ser. No. 07/567,390entitled ELECTRICAL CONTROL SYSTEM FOR VEHICLE OPTIONS, filed on Aug.14, 1990, the disclosures of which are incorporated herein by referencethereto.

BACKGROUND OF THE INVENTION

The invention relates to a control system for a vehicle, and moreparticularly, to a system for controlling vehicle options responsive toa keyless entry remote control signal and for learning and selectivelytransmitting control signals for actuating a garage door openingmechanism.

Keyless entry systems including a remote keyless entry (RKE) transmitterwhich transmits a radio frequency (RF) control signal and a vehiclereceiver which detects the RF control signal from the RKE transmitter tocontrol vehicle door locks responsive thereto are well known. RF remotecontrols for actuating garage door mechanisms from a vehicle are alsowell known. These systems typically include separate circuitry since thegarage door opening remote control is typically a transmitter which ismounted within a housing that the car owner may store in the vehicle,but is not integrated into the vehicle electrical system whereas thekeyless entry receiver includes an RF receiver which is integrated intothe vehicle electrical system. The separate circuitry is also necessarybecause the garage door opening mechanism and the keyless entry systemoperate at different frequencies, have different signaling formats, anduse different security codes.

A novel keyless entry receiver and a garage door opener remote controlis disclosed in U.S. patent application Ser. No. 07/567,390 entitledELECTRICAL CONTROL SYSTEM FOR VEHICLE OPTIONS, filed Aug. 14, 1990,which is incorporated hereinabove by reference, and assigned to the sameassignee as the immediate invention. The system of U.S. patentapplication Ser. No. 07/567,390 has an integrated trainable transceiverwhich receives RF signals from garage door opener remote control in alearning mode and transmits a garage door opener remote control signalwhich it has previously learned for actuating a garage door openermechanism without the separate remote control in a transmit mode. Thetrainable transceiver also receives a keyless entry control signal froman RF RKE transmitter. Although this trainable transceiver providesimproved versatility and operating characteristics over prior arttrainable transmitters, still further improvements in the operatingcharacteristics of an integrated trainable transceiver and keyless entryreceiver are desired. Thus, it remains desirable to improve thesignal-to-noise characteristics of the transceiver. It is also desirableto improve transceiver characteristics in the receive modes for thekeyless entry operation and garage door opener operation. Because thetransceiver operates when the vehicle's engine is not running, it isalso desirable to improve the power consumption characteristics of thetrainable transceiver.

SUMMARY OF THE INVENTION

The present invention provides a transceiver having an improvedintegrated trainable transmitter and vehicle operation control systemfor a vehicle. The transceiver includes an input circuit receiving radiofrequency signals from a garage door opener remote control in a trainingmode and from a separate transmitter in a transmitter detection mode.The transceiver also includes an output circuit generating radiofrequency signals for actuating a device controlled by the remotecontrol. A controller detects signals from the input circuit andcontrols the output circuit while an interface circuit couples thecontroller to the vehicle's electrical system for controlling vehicleoptions in response to received signals.

According to a first aspect of the invention, the input circuit includesan amplitude control which is used to adjust the sensitivity (i.e.,reception range) of the transceiver. According to another aspect of theinvention, the transceiver disconnects the output circuit from anantenna associated therewith when the controller is in a remote controltraining mode or a reception mode. According to another aspect of theinvention, the controller is responsive to a first input signal tooperate in a receive mode, to a second user initiated control signal tooperate in a transmit mode, and to a third signal which is automaticallygenerated for initiating reception of a signal from said remotetransmitter.

The system according to the invention integrates a trainable remotecontrol for actuating devices remote from the vehicle and a receiver tocontrol a vehicle option responsive to a signal from a remotetransmitter. The input circuit amplifier variable gain adjusts thecircuit such that it has a significantly less sensitivity in remotecontrol training mode than in a transmitter signal reception mode. Thesystem also has a significantly improved signal to noise ratio forreceived signals by eliminating noise which may otherwise be conveyedfrom the output circuit to the input circuit of the transceiver. Thesystem also provides more versatile operation, allowing user control aswell as automatic power control, thereby effecting power savings.

These and other aspects, features and advantages of the presentinvention will become apparent upon reading the following descriptionthereof, together with reference to the accompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a pictorial view of a vehicle including a transceiveraccording to the present invention;

FIG. 2 is a perspective view of a receiver housing according to theinvention;

FIG. 3 is an opposite perspective view of a transceiver housingaccording to FIG. 2;

FIG. 4 is a circuit schematic of the transceiver according to theinvention shown in block diagram form; and

FIG. 5 is a flow diagram of the program for controlling the operation ofthe transceiver according to FIG. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring initially to FIGS. 1-3, a vehicle 8 is illustrated including atransceiver 12 according to the invention. The invention is integratedinto a small, generally square module housing 10. Housing 10 encloses atransceiver 12 (FIG. 4) which selectively transmits coded radiofrequency (RF) energy, as indicated by arrow "T" to a device controlledby an RF control signal, such as a garage door opening mechanism 14shown in block form in FIGS. 1 and 4. The conventional garage dooropening mechanism 14 includes a receiver and control circuit (not shown)which responds to the control signal "T" for opening and closing agarage door. Transceiver 12 includes a programmable microcontroller 16(FIG. 4) which controls an RF output circuit 18 to generate signal "T."Signal "T" has a frequency and code learned from signal "B" transmittedby existing remote control transmitter 20 and identified by transceiver12 in a training mode, as described in greater detail in U.S. patentapplication Ser. No. 07/874,361, incorporated hereinabove by referencethereto. The transceiver, after learning the carrier frequency, formatand code of signal "B," can transmit remote control signal "T" toactivate the garage door opening control mechanism 14 without furtherneed for the remote control transmitter 20. Transmitter 20 is typicallyprovided with garage door opening mechanism 14 and generates controlsignal "B" for remotely actuating the garage door opening mechanism, butsuffers from the storage and use problems described in co-pending patentapplication Ser. No. 07/567,390, incorporated hereinabove by reference.

Transceiver 12 also responds to control signals "K" from keyless entryremote control 22. An RF input circuit 19 demodulates signal "K" andoutputs control signals to the vehicle electrical system responsivethereto. For example, the keyless entry remote control may controlvehicle door locks, a trunk lock and a gas door cover. Responsive tosignal "K," the microcontroller outputs a control signal to serial bus24 which controls the vehicle accessories or options according to theinput control code.

Housing 10 is small, such that it may be integrated into a variety ofaccessories in the vehicle, such as in a rearview mirror, an overheadconsole, a map light, a visor, the instrument panel, or any othersuitable location in the vehicle. The transmitter includes threeswitches 26, 27 and 28 in a front panel face 30. Each switch isassociated with a respective channel, and each channel stores arespective RF control signal in a training mode for remotely actuatingone device. For example, the three channels may have three signalsassociated with three respective garage door opening mechanisms.Alternatively, two of the channels can have signals for two, respective,garage door openers, and the third channel can have a signal forcontrolling an interior house light, exterior house lights, or the like.

Each of switches 26-28 is used both to train and to actuate itsrespective channel. For example, if one of these switches is held forless than a predetermined period (e.g., less than 5 seconds),transceiver 12 will transmit the signal stored for that channel. If theswitch is held for longer than the predetermined time period,microcontroller 16 will enter the training mode for the control channelassociated with that held switch. An LED 32 is provided on front panelface 30 to inform the operator of the operational mode. For example, theLED is illuminated continuously while a signal is being transmitted,flashes in the training mode, and flashes at a rate five times fasterthan the training mode rate when the training mode is finished.

It is envisioned that a fourth switch (not shown) can be provided onhousing 10 which is actuated to initialize a training mode fortransceiver 12 whereby the trainable transceiver learns transmittersignal "K" from a new transmitter which can be used after training tocontrol vehicle options.

The back panel 40 includes a connector 42 for connection to the vehicleelectrical system serial bus 24. This connector 42 mates with acomplementary connector 43 (FIG. 4), which is coupled to a vehicleserial bus 24, when the housing is installed in the vehicle. The serialbus may, for example, be a multiplexing bus having two, four, ten ormore conductors and connected to a main microcontroller (not shown) forthe vehicle electrical system. The microcontroller 16 thus communicateswith vehicle accessories through the multiplex bus on the vehicle. Itwill be appreciated by those skilled in the art that microcontroller 16may be connected to the vehicle electrical system microcontroller or itmay be connected directly to the vehicle options being controlled, aswill be required by the vehicle electrical system.

Although the overall preferred mounting environment is described withrespect to the generally square housing 10, transceiver 12 according tothe invention may be used in other environments. For example, theimproved transmitter of the immediate invention may be used as anintegral part of a rearview mirror such as that disclosed in U.S. patentapplication Ser. No. 07/567,390, the disclosure of which is incorporatedhereinabove by reference thereto, or as an integral part of a sun visor,an overhead console, or the like.

Having briefly described the overall preferred mounting environment andoperation of transmitter 12, and its relationship to a vehicle, adetailed description of the preferred embodiment is now presented inconnection first with the circuit diagram of FIG. 4, and subsequentlywith reference to the flow diagram of FIG. 5.

Operation of transceiver 12 is controlled by microcontroller 16.Transceiver 12 includes a power supply 45, a user input 46 forcontrolling the microcontroller 16, an interrupt circuit 47 generatingan external interrupt and responsive to a reset signal for restarting atimer in the interrupt circuit, a user output 48 providing informationto the operator, and a connector 42 connected to serial bus 24, which inturn is connected to the vehicle electrical system. An RF signal inputcircuit 19 and the RF signal output circuit 18 are connected tomicrocontroller 16 for receiving and transmitting RF signals.

The user input 46 (FIG. 4) and the user output 48 provide an operatorinterface. The user input includes switches 26-28 (FIG. 2) which aredisclosed in U.S. Pat. No. 5,442,340 or the switches disclosed in U.S.patent application Ser. No. 07/567,390 entitled ELECTRICAL CONTROLSYSTEM FOR VEHICLE OPTIONS. As described above, the switches provideoperator actuated control of the training and transmitting mode for thetrainable transceiver 12 (FIG. 4) which controls device 14 withoutremote control 20. The user output 48 includes visual indicator 32 or avacuum fluorescent display as disclosed in application Ser. No.07/567,390. The visual indicator 32 indicates the operating mode of thetrainable transceiver by constant illumination or various flashingrates. If the system is used with a compass or a thermometer, the useroutput 48 may include an alpha-numeric display. The alpha-numericdisplay would provide additional information such as vehicle heading andoutside temperature information, as described in parent application Ser.No. 07/567,390. Microcontroller 16 is also connected to power supply 45,which provides a regulated supply voltage and a standby enable signal.Power supply 45 and the standby enable signal are described in U.S. Pat.No. 5,442,340 incorporated herein by reference thereto.

The RF signal output circuit 18 includes a phase locked loop circuit 51connected to the frequency output 57 of microcontroller 16 through aparallel data bus 52. The phase locked loop circuit 51 is implementedusing any suitable integrated circuit such as the Motorola MC145106,driven by an 8 MHz oscillator. The phase locked loop 51 is responsive tothe frequency selection signals at output 57 of microcontroller 16 togenerate a DC signal at output 59.

The output signal at output 59 of the phase locked loop circuit 51 isfiltered in lowpass filter 54. The output of the lowpass filter isconnected to a switch 56. Switch 56 is connected to output 50 ofmicrocontroller 16. A sample-and-hold circuit 58 is connected to switch56 and holds the signal output from the low-pass filter during afrequency selection interval. The sample-and-hold circuit may beimplemented using any suitable means such as an IC No. 4066 switch, acapacitor and an amplifier.

The output of sample-and-hold circuit 58 is the DC control signal for avoltage controlled oscillator (VCO) 60. The frequency of the oscillatingsignal output by VCO 60 is set by the DC signal output fromsample-and-hold circuit 58. The VCO includes a switch (not shown), whichmay be implemented using a transistor, and which is switched on and offunder the control of a data signal at input 64. Input 64 is connected tooutput 63 of microcontroller 16 by conductor 61. The VCO enable signalat output 63 switches VCO 60 on and off according to data signals storedin microcontroller 16, which data is learned in the garage door openerremote control training mode.

The signal output by VCO 60 is filtered in lowpass filter 65. Theamplitude of the signal output by the lowpass filter is controlled by anattenuator 67. Attenuator 67 is preferably implemented by a plurality ofseries circuits, each of which comprises a respective transistor (notshown) and a resistor (not shown) connected in series between the outputof VCO 60 and ground. The attenuator is connected to output 66 ofmicrocontroller 16 through a data bus 73. Data bus 73 has a respectiveconductor for each series circuit in attenuator 67. The transistors areeach connected to a respective conductor of bus 73 such that they areselectively turned on and off under the control of microcontroller 16.The output signal of the attenuator 67 is input to a buffer 62. Buffer62 may be implemented by any suitable buffer circuit, such as a unitygain amplifier or an emitter-follower transistor configuration. Theoutput of buffer 62 is connected to one terminal 68 of a switch 70, aninput 69 of phase locked loop 51, and to one input 71 of a mixer 72.

Switch 56 is controlled such that the signal output from filter 54 ismomentarily input to the sample-and-hold circuit 58 at the beginning ofa frequency select interval. When a new frequency is output, or if thesample-and-hold circuit requires refreshing, the switch is closed andthe signal output from lowpass filter 54 is sampled again. This controlof switch 56 prevents oscillation or other variations of the controlsignal input to VCO 60. Accordingly, the VCO 60 will generate a stableoutput signal during the frequency interval. The output of buffer 62 isan oscillating signal having a carrier frequency set by the signal onparallel data bus 52.

The transceiver 12 includes an antenna 74 which is connected to contact76 of switch 70. Switch 70 is coupled to output 75 of microcontroller16. The switch may be implemented by any suitable switch such as a relaydriven by the output signal of microcontroller 16. Switch 70 iscontrolled by signals from microcontroller 16 such that the contact 76connects antenna 74 to terminal 78 in the receive state. In the transmitstate, the contact connects antenna 74 to terminal 68. The switch isthus used to selectively isolate the antenna 74 from the output of thebuffer 62 in the receive state, thereby enhancing circuit performance byreducing noise in the received signal which would otherwise result fromthe coupling of the input and output circuits.

Although transceiver 12 preferably includes a single antenna 74, thoseskilled in the art will recognize that two antennae (not shown) could beused: one for the RF signal input circuit and one for the RF signaloutput circuit. If such separate antennae are provided, a respectiveswitch (not shown) would be connected between each antenna and itsassociated circuit. The switches would then be controlled such that onlyone is closed at any given time.

The RF signal input circuit 19 includes mixer 72, which has a firstinput 77 connected to contact 76 and a second input 71 connected to theoutput of buffer 62. The mixer combines the signal detected by antenna74 with the oscillating signal output by buffer 62. The output signal ofthe mixer 72 is filtered by bandpass filter 84. The bandpass filter 84removes noise from the output of the mixer 72. The filtered signal isinput to an intermediate frequency amplifier 88 having a gain controlinput 90. Gain control input 90 is connected to output 92 ofmicrocontroller 16. The IF amplifier 88 may be implemented using anysuitable means such as an amplifier with a variable feedback impedance.The gain control input signal varies the amplifier gain between threelevels. The amplifier is controlled to have a high gain level forreceiving signals from transmitter 22 and a low gain when training to asignal B from remote control 20. The IF amplifier 88 has a low gain whentransceiver 12 is in a training mode to reduce the sensitivity of thereceiver, and thereby lower the range, such that only those signalstransmitted from a source within a radius of approximately 1 to 10 feetare detected. This insures that the transceiver learns a signal from thedesired remote control and does not detect signals from any nearby RFtransmitters. In a transmitter detection mode, for inputting a signalfrom transmitter 22, the gain of amplifier 88 is controlled to providethe transceiver with a significantly greater sensitivity. This allowstransceiver 12 to detect a signal from a keyless entry transmitter 22while the user is still several car lengths away from vehicle 8 (FIG.1). When transceiver 12 (FIG. 4) is not in the training mode or thetransmitter detection mode, the gain of the IF amplifier can becontrolled to be at substantially OdB, to prevent noise from the receivecircuit being input to controller 16.

The output of the IF amplifier 88 is input to an AM demodulator 93. Theoutput of demodulator 93 is input to a data amplifier 94. The dataamplifier includes a comparator which compares the signal output fromthe demodulator 93 to a fixed reference signal. If the output ofdemodulator 93 exceeds the reference signal, the comparator outputs ahigh logic level signal. Otherwise, the comparator outputs a low logiclevel signal. The output of the data amplifier 94 is connected to input99 of microcontroller 16.

The interrupt circuit, or sleep timer, 47 is connected to input 98 andoutput 97 of microcontroller 16. The sleep timer is connected to input98 of microcontroller 16. Sleep timer 47 is implemented using anysuitable low power consumption timer which outputs a timer interruptsignal a predetermined time period after it is reset by the reset signalfrom microcontroller 16.

The circuit represented by FIG. 4 is a self-contained trainabletransmitter for the environment illustrated in FIG. 1. It will berecognized that the user interface and microcontroller 16 will includeadditional inputs and outputs when utilized in the environmentillustrated in FIG. 2 of application Ser. No. 07/567,390. The mainprograms for the microcontroller 16 of trainable transceiver 12 is shownin co-pending patent application Ser. No. 07/567,390 and U.S. Pat. No.5,479,155, the disclosures of which are incorporated herein by referencethereto. Accordingly, those programs will not be described in greaterdetail herein.

The reset/power-up operation will now be described with reference toFIG. 5 and the circuit of FIG. 4. Microcontroller 16 initiatestransmit/receive state control following an external interrupt generatedby the sleep timer 47, upon power-up of microcontroller 16, or when oneof switches 26-28 is actuated. Microcontroller 16 (FIG. 4) firstdetermines whether one of switches 26-28 (FIG. 2) is actuated, asindicated in block 100 (FIG. 5). If one of switches 26-28 was actuated,microcontroller 16 determines that the transmit/receive operation to beperformed pertains to the garage door opener remote control operation,as indicated in block 102. If one of switches 26-28 is not actuated,microcontroller 16 determines that the transmitter was powered up orthat interrupt timer 47 generated an interrupt signal, as indicated inblock 104.

If microcontroller 16 determines that one of switches 26-28 is actuated,the microcontroller transmits a signal as indicated in block 106. Totransmit an signal, microcontroller 16 outputs a signal at output 75which controls switch contact 76 to connect antenna 74 to buffer 62through terminal 68. Microcontroller 16 then outputs a control signal atoutput 57 which controls the phase locked loop 50 to output a DC signalwhich drives the VCO 60 to have a desired carrier frequency which waspreviously stored in association with the one of the switches 26-28which is actuated. Microcontroller 16 also outputs a data signal atoutput 63 which controls voltage controlled oscillator 60 to turn on andoff according to the data signals stored for that actuated switch.

As indicated in decision block 108, microcontroller 16 continues tomonitor the actuated switch, while the transceiver is transmitting thesignal. If microcontroller 16 determines that the switch is actuated forlonger than a predetermined minimum time period (e.g., 5 seconds), themicrocontroller switches to a training mode, as determined in block 110.The microcontroller then performs the training routine, as indicated inblock 112, and which is described in greater detail in U.S. Pat. No.5,479,155. In the training routine, the microcontroller outputs a signalat output 75 which controls contact 78 to connect antenna 74 to input77. The microcontroller also outputs a signal at output 92 whichcontrols the output amplitude of the IF amplifier 88 to be at a lowlevel which limits the reception range of the transceiver during thetraining mode. The microcontroller also controls the phase locked loopto generate those carrier frequency signals at which garage door openingmechanism remote controls are known to operate (e.g., in the rangebetween approximately 200 MHz and 400 MHz). Microcontroller 16 remainsin the training mode until the training operation is completed, asdetermined in block 116.

If the actuated switch was released before the predetermined minimumtime period is finished as determined in block 108, or upon completionof the training sequence as determined in block 116, or if it wasdetermined in decision block 100 that one or more of the switches 26-28were not actuated, microcontroller 16 performs a remote transmitterdetection operation. To detect incoming data, microcontroller 16 outputsa signal on output 53 which controls VCO 60 to output a signal at thefrequency of keyless entry transmitter 22. For example, themicrocontroller outputs a signal which controls the output circuit togenerate a signal at 310 MHz if the RKE transmitter operates at 310 MHz.Microcontroller 16 also outputs a control signal at output 92, whichcontrols the RF input circuit IF amplifier to have a high gain, and asignal at output 75, which controls contact 75 to connect antenna 74 toinput 77 of mixer 72. Microcontroller 16 then monitors input 78 todetermine whether any data is being output by the comparator, asindicated in decision block 120. If data is detected, microcontroller 16determines whether the data corresponds to a particular identificationcode stored in microcontroller 16 or whether the data has an appropriatesignal to noise ratio, as indicated in block 122. If the datacorresponds to a code stored in microcontroller 16, the microcontrollerevaluates the inputs thereto as indicated in block 124. The inputsevaluated include the serial bus and any other input which would effecthow an output action is to be taken. For example, if the serial busindicates that all the doors are unlocked when remote transmitter 22command is to unlock the doors, microcontroller 16 would not have tounlock the doors. The microcontroller would effect illumination of thevehicle interior by controlling switches (not shown) to connect theinterior lamps (not shown) to the vehicle battery (not shown). Themicrocontroller is thus responsive to the input conditions and thecontrol signals received from transmitter 22 to perform a selectedoutput action at block 126.

Following a decision in block 120 that data is not incoming fromtransmitter 20, or a decision in block 122 that the data is not OK, orfollowing an action in block 126, microcontroller 16 puts itself in asleep mode to conserve power. In the sleep mode, the microcontroller haslimited operating functions which lower the power consumption of thetransceiver. In this mode, the microcontroller periodically monitors theinputs thereto to determine if an interrupt signal has been generated bythe interrupt timer 47 or if one of the switches 26-28 has beenactuated. To enter the sleep mode, microcontroller 16 first outputs areset signal at output 97 which is input to the timer as indicated inblock 128. This reinitializes the timer. The microcontroller then goesto sleep as indicated in block 130. When the timer expires, an externalinterrupt is generated thereby which interrupts the microcontrollersleep mode and microcontroller 16 returns to a fully operating state, asindicated at block 100.

Thus, it can be seen that a transceiver is disclosed which providesimproved control for switching between a remote keyless entry mode and atransmitter mode. The circuit has improved input amplitude control andnoise suppression. Additionally, the transmitter conserves energy byoperating in a sleep mode.

It will become apparent to those skilled in the art that variousmodifications to the preferred embodiment described and disclosed hereincan be made. Such modifications will, however, fall within the spirit orscope of the invention as defined in the appended claims unless theclaims by their language express state otherwise.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. A trainable transceiversystem for a vehicle, comprising:a transceiver operable in one of aplurality of operating modes including a training mode, a signaltransmission mode, and a transmitter signal detection mode, saidtransceiver including an input circuit for receiving radio frequencysignals transmitted from a remote control transmitter and from a secondtransmitter, said input circuit including a variable amplitudecontroller having an amplitude control input; and a control circuitcoupled to said amplitude control input of said input circuit forselectively varying the amplitude of said variable amplitude controllerto decrease the sensitivity of said input circuit when said transceiveris operating in the training mode for receiving signals from said remotecontrol transmitter and, when said transceiver is in said signaldetection mode, said control circuit receives signals from said secondtransmitter.
 2. The transceiver system as defined in claim 1, whereinsaid transceiver further includes an output circuit coupled to saidcontrol circuit for selectively generating radio frequency signals underthe control of said control circuit.
 3. The transceiver system asdefined in claim 1, wherein said variable amplitude controller fullyattenuates a signal input thereto when said transceiver is not operatingin the transmitter signal detection mode or in the training mode.
 4. Thetransceiver system as defined in claim 2, further including an antennaand a switch for selectively connecting said output circuit to saidantenna, said control circuit coupled to said switch to control saidswitch.
 5. The transceiver system as defined in claim 2, furtherincluding a user actuated selector and an interrupt timer forcontrolling said transceiver to change operating modes.
 6. A trainabletransceiver system for a vehicle having an electrical system,comprising:a transceiver operable in one of a plurality of operatingmodes including a training mode, a signal transmission mode, and atransmitter signal detection mode, said transceiver includingan inputcircuit for receiving radio frequency signals transmitted from aseparate remote control for a garage door opening device and the radiofrequency signal transmitted from a remote transmitter for controllingvehicle option operation, said input circuit including an amplitudecontroller having an amplitude control input, and an output circuit,responsive to output control signals, for selectively generating radiofrequency control signals for actuating the garage door opening devicewithout the separate remote control; an interface circuit coupled to theelectrical system of the vehicle; and a controller coupled to said inputcircuit, said output circuit, and to said interface circuit, whereinwhen said transceiver is in a training mode, said controller receivessignals from said input circuit, and stores information about thereceived signals, when said transceiver is in the signal transmissionmode, said controller selectively provides output control signals tosaid output circuit, when said transceiver is in the transmitter signaldetection mode, said controller selectively provides option controlsignals to said interface circuit to control operation of the vehicleelectrical system in response to a detected signal from the remotetransmitter, and wherein said controller provides amplitude controlsignals to said amplitude control input to selectively adjust thesensitivity of said transceiver according to the operating mode of thetransceiver.
 7. The transceiver system as defined in claim 6, whereinsaid amplitude controller includes a variable gain amplifier.
 8. Thetransceiver system as defined in claim 7, wherein said variable gainamplifier has a gain control input coupled to said controller, andwherein said amplitude control signal is input to said gain controlinput such that said input circuit has a lower sensitivity when saidtransceiver is in the training mode to learn the remote control signalfrom the remote control and a greater sensitivity when the transceiveris receiving a signal from the remote transmitter while in thetransmitter signal detection mode.
 9. The transceiver system as definedin claim 8, wherein said amplitude controller fully attenuates a signalinput thereto when said transceiver is not in the transmitter signaldetection mode or in the training mode.
 10. The transceiver system asdefined in claim 6, wherein said amplitude controller includes avariable attenuator.
 11. The transceiver system as defined in claim 10,wherein said variable attenuator is coupled to said controller, andwherein said amplitude control signal is input to said variableattenuator such that said input circuit has a lower gain when thetransceiver is in the training mode and a higher gain when thetransceiver is in the transmitter signal detection mode.
 12. Thetransceiver system as defined in claim 11, wherein said variableattenuator fully attenuates a signal input thereto when said transceiveris not in a transmitter signal detection mode or in a training mode. 13.The transceiver system as defined in claim 6, including an antenna and aswitch for selectively connecting said output circuit to said antenna,said controller coupled to said switch to control said switch.
 14. Thetransceiver system as defined in claim 6, further including a useractuated selector and an interrupt timer for controlling saidtransmitter to change operating modes.
 15. A trainable transceiversystem for a vehicle, comprising:a transceiver operable in one of aplurality of operating modes including a training mode, a signaltransmission mode, and a transmitter signal detection mode, saidtransceiver including an input circuit for receiving radio frequencysignals transmitted from an RF remote control transmitter forcontrolling a garage door opening device, and from a remote keylessentry transmitter, said input circuit including a variable amplitudecontroller having an amplitude control input; and a control circuitcoupled to said amplitude control input of said input circuit forselectively varying the gain of said amplitude controller to decreasethe sensitivity of said input circuit when said transceiver is operatingin the training mode for receiving signals from said RF remote controltransmitter and, when said transceiver is in said signal detection mode,said control circuit receives signals from said keyless entrytransmitter.
 16. A trainable transceiver system for a vehicle,comprising:a transceiver operable in one of a plurality of operatingmodes including a training mode, a signal transmission mode, and atransmitter signal detection mode, said transceiver including an inputcircuit for receiving radio frequency signals transmitted from an RFremote control transmitter for controlling a garage door opening device,and from a remote keyless entry transmitter, said input circuitincluding a variable amplitude controller having an amplitude controlinput; and a control circuit coupled to said amplitude control input ofsaid input circuit for selectively varying the gain of said amplitudecontroller to decrease the sensitivity of said input circuit when saidtransceiver is operating in the training mode for learning the RFfrequency and code of signals from said RF remote control transmitterand, when said transceiver is in said signal detection mode, saidcontrol circuit receives signals from said keyless entry transmitter.17. A trainable transceiver system for a vehicle having electronicvehicle door locks, comprising:a transceiver operable in one of aplurality of operating modes including a training mode, a signaltransmission mode, and a transmitter signal detection mode, saidtransceiver including an input circuit for receiving radio frequencysignals transmitted from an RF remote control transmitter forcontrolling a garage door opening device, and from a remote keylessentry transmitter for actuating said vehicle door locks, wherein saidtransceiver includes an output circuit for generating RF signals foractuating a controlled device during a signal transmission mode, saidoutput circuit having an output at which RF signals are output, whereinsaid output circuit further includes a first amplitude controller forcontrolling the transmission range of the transceiver: a control circuitcoupled to said vehicle door locks and to said input circuit forlearning the RF frequency and code of signals received from said RFremote control transmitter when said transceiver is operating in thetraining mode and for receiving signals from said keyless entrytransmitter and supplying an actuation signal to said vehicle door locksin response to the receipt of a signal from said keyless entrytransmitter when said transceiver is in said signal detection mode; anantenna; and a switch coupled between said output of said output circuitand said antenna, said switch having a control input at which a controlsignal is input which controls a state of said switch, and wherein saidcontrol circuit is coupled to said input circuit, to said output circuitand to said switch, to control said switch to disconnect said output ofsaid output circuit from said antenna when said transceiver is operatingin either said training mode or said transmitter signal detection mode,wherein said switch is coupled to an input of said input circuit and tosaid output of said output circuit, said switch responsive to signalsfrom said control circuit for connecting said antenna to said input ofsaid input circuit when said transceiver is receiving a signal.
 18. Thetrainable transceiver system as defined in claim 17, wherein said inputcircuit includes a second amplitude controller for controlling thereception range of the transceiver.
 19. A trainable transceiver systemfor a vehicle having electronic vehicle door locks, comprising:atransceiver operable in one of a plurality of operating modes includinga training mode, a signal transmission mode, and a transmitter signaldetection mode, said transceiver including an input circuit forreceiving radio frequency signals transmitted from an RF remote controltransmitter for controlling a garage door opening device, and from aremote keyless entry transmitter for actuating said vehicle door locks,wherein said transceiver includes an output circuit for generating RFsignals for actuating a controlled device during a signal transmissionmode, said output circuit having an output at which RF signals areoutput; a control circuit coupled to said vehicle door locks and to saidinput circuit for learning the RF frequency and code of signals receivedfrom said RF remote control transmitter when said transceiver isoperating in the training mode and for receiving signals from saidkeyless entry transmitter and supplying an actuation signal to saidvehicle door locks in response to the receipt of a signal from saidkeyless entry transmitter when said transceiver is in said signaldetection mode; an antenna; a switch coupled between said output of saidoutput circuit and said antenna, said switch having a control input atwhich a control signal is input which controls a state of said switch,and wherein said control circuit is coupled to said input circuit, tosaid output circuit and to said switch, to control said switch todisconnect said output of said output circuit from said antenna whensaid transceiver is operating in either said training mode or saidtransmitter signal detection mode; a user interface coupled to saidcontrol circuit and including actuators for inputting first and secondcontrol signals; and an interrupt signal generator coupled to saidcontrol circuit for generating a third control signal, wherein saidcontrol circuit controls said transceiver to operate in said signaltransmission mode in response to said first signal from said userinterface, said control circuit controls the transceiver to operate insaid training mode in response to said second control signal from saiduser interface, and said control circuit controls the transceiver toenter a transmitter signal detection mode in response to said thirdcontrol signal.
 20. The trainable transceiver system as defined in claim19, wherein said interrupt signal generator includes an interrupt timerfor periodically generating said third control signal.
 21. The trainabletransceiver system as defined in claim 20, wherein said control circuitcontrols said transceiver to enter a sleep mode when said first, second,and third control signal has not been received, and wherein said controlcircuit initializes said interrupt timer upon entering a sleep modewhereby said interrupt timer interrupts the sleep mode automatically atthe end of a sleep interval by generating said third control signal. 22.The trainable transceiver system as defined in claim 19, wherein saidcontrol circuit controls said transceiver to enter said transmittersignal detection mode following said training mode or said transmitmode.
 23. A trainable transceiver system for a vehicle having electronicvehicle door locks, comprising:a transceiver operable in one of aplurality of operating modes including a training mode, a signaltransmission mode, and a transmitter signal detection mode, saidtransceiver including an input circuit for receiving radio frequencysignals transmitted from an RF remote control transmitter forcontrolling a garage door opening device, and from a remote keylessentry transmitter for actuating said vehicle door locks; a controlcircuit coupled to said vehicle door locks and to said input circuit forlearning the RF frequency and code of signals received from said RFremote control transmitter when said transceiver is operating in thetraining mode and for receiving signals from said keyless entrytransmitter and supplying an actuation signal to said vehicle door locksin response to the receipt of a signal from said keyless entrytransmitter when said transceiver is in said signal detection mode; auser interface coupled to said control circuit and including actuatorsfor inputting first and second control signals; and an interrupt signalgenerator coupled to said control circuit for generating a third controlsignal, wherein said control circuit controls said transceiver tooperate in said signal transmission mode responsive to said first signalfrom said user interface, said control circuit controls the transceiverto operate in said training mode responsive to said second controlsignal from said user interface, and said control circuit controls thetransceiver to enter a transmitter signal detection mode responsive tosaid third control signal.
 24. The trainable transceiver system asdefined in claim 23, wherein said interrupt signal generator includes aninterrupt timer for generating said third control signal.
 25. Thetrainable transceiver system as defined in claim 24, wherein saidcontrol circuit controls said transceiver to enter a sleep mode whensaid first, second, and third control signal has not been received, andwherein said control circuit initializes said interrupt timer uponentering a sleep mode whereby said interrupt timer interrupts the sleepmode automatically at the end of a sleep interval by generating saidthird control signal.
 26. The trainable transceiver system as defined inclaim 23, wherein said control circuit controls said transceiver toenter said transmitter signal detection mode following said trainingmode or said transmit mode.
 27. The trainable transceiver system asdefined in claim 23, wherein said first control signal is generated whenan actuator of said user interface is actuated for a first predeterminedtime period.
 28. The trainable transceiver system as defined in claim27, wherein said second control signal is generated when an actuator ofsaid user interface is actuated for a second predetermined time period.